This description relates to mitigation of inter-network interference to enable channel reuse.
Communications systems such as cellular communication systems, power line communication systems, and wireless local area network systems use electromagnetic signals to exchange information. Electromagnetic signals get attenuated and distorted as they propagate through media. In general, signal attenuation increases as the distance between a receiver and a transmitter increases. Signal distortion depends on the medium through which the signal propagates. In addition to getting attenuated and distorted, signals also get corrupted due to noise in the medium. Accordingly, in communication systems, a signal can only be properly received if the signal-to-noise ratio at the receiving station is high enough. The signal-to-noise ratio thus limits the range of separation between the transmitter and receiver for successful communication. For example, the range of electromagnetic signals in cellular networks is several miles while the range of signals in a WiFi system is a few hundred feet.
Communication signals that propagate on the same medium and which overlap in time and frequency may interfere with each other and prevent accurate reception at an intended receiver. In some cases overlap of communication signals on the medium can be tolerated if the power level of the desired signal at the intended receiver is large enough in relation to the power level of any interfering signals at the receiver. For example, cellular networks may use a priori knowledge of the geographic positions of base stations to reuse the transmission frequencies in two cells that are sufficiently distant from each other for interference between the two cells to be tolerable. This allows those stations to reuse overlapping frequency channels without coordinating their transmissions. Alternatively, the medium may be shared by coordinating transmissions to avoid overlap in time or frequency.
For example, power line communications utilize existing wired infrastructure in homes and buildings to provide high throughput multimedia connectivity. As the market continues to grow for this technology, its challenges must be successfully addressed to meet practical as well as regulatory requirements. One such problem is the efficient use of the wired medium in a multiple dwelling unit (MDU) scenario. Deployment of multiple uncoordinated and independent networks on a common medium results in random collisions. A solution to this problem is to coordinate the networks and have them share the medium's resources equally. Using this approach the throughput of each network is reduced in proportion to the number of neighboring networks but collisions are avoided.